Lung cancer is the leading cause of cancer deaths in the United States in both men and women. Approximately 3/4 of all lung cancers are nonsmall cell lung cancers (NSCLC), and most patients with this disease will die due to metastatic disease. Thus, improved therapy for metastatic disease is an urgent priority. Cisplatin is the most active standard chemotherapy agent against NSCLC, however whether as a single agent or in combination, its impact on survival is minimal. One possible reason for the limited efficacy of chemotherapy in this disease is the presence of hypoxic tumor cells, which may make up 12-35% of the tumor. Such cells are known to be resistant in vitro to radiation therapy and most chemotherapy agents. Tirapazamine is an investigational agent which is selectively toxic to gypoxic cells. In some tumor models, the combination of tirapazamine and cisplatin has demonstrated synergistic cell kill, and in Phase I/II trials, this combination has demonstrated activity against NSCLC in patients. This trial is designed to determine whether the combincation of cisplatin and tirapazamine will improve survival over cisplatin alone in patients with advanced and metastatic NSCLC.